In general, a receiver of a wireless communication system receives signals through a multipath at different times, demodulates the received signals in respective paths, removes a time delay, combines signals of the respective paths, and performs decoding. Herein, an apparatus performing independent demodulation and combination on a multipath signal is generally referred to as a rake receiver.
A conventional rake receiver includes a channel estimator that estimates a channel of each path. The conventional rake receiver compensates for a channel gain value output from the channel estimator, and performs Maximum Ratio Combining (MRC). The MRC has the best effect when there is no estimation error in the channel gain value output from the channel estimator.
However, the channel estimator of the conventional rake receiver has an estimation error in the channel gain value according to a moving speed of a terminal and a Signal-to-Noise Ratio (SNR) of an input signal. Therefore, there is a need to apply a weight capable of maximizing an SNR of a rake receiver, considering an estimation error in the channel gain value output from a channel estimator.